From: Ulf Hansson <ulf.hansson@linaro.org>
To: Corey Gao <gaoce123@gmail.com>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mmc: core: Add error check to avoid kernel panic caused by NULL pointer
Date: Tue, 16 Jun 2020 13:26:10 +0200 [thread overview]
Message-ID: <CAPDyKFrUNVryOCn0VqoATOgvJq5H7XPNb79tw+yxTV3wOqsVFQ@mail.gmail.com> (raw)
In-Reply-To: <20200602172957.13592-1-gaoce123@gmail.com>
On Tue, 2 Jun 2020 at 19:31, Corey Gao <gaoce123@gmail.com> wrote:
>
> If __mmc_start_req(host, mrq) fails with error, the mrq->cmd->mrq will
> be NULL. This will cause kernel panic in the following
> mmc_wait_for_req_done(host, mrq). Add error check to cancle unnecessary
> mmc_wait_for_req_done(host, mrq) if __mmc_start_req(host, mrq) fails.
The above is a bit hard for me to follow, can you please try to
elaborate on the problem. Moreover, please, provide a stack trace, as
that is easier to follow for me.
Kind regards
Uffe
>
> Signed-off-by: Corey Gao <gaoce123@gmail.com>
> ---
> drivers/mmc/core/core.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 2553d903a82b..b13b484e64aa 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -734,9 +734,11 @@ EXPORT_SYMBOL(mmc_start_req);
> */
> void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
> {
> - __mmc_start_req(host, mrq);
> + int err;
>
> - if (!mrq->cap_cmd_during_tfr)
> + err = __mmc_start_req(host, mrq);
> +
> + if (!mrq->cap_cmd_during_tfr && !err)
> mmc_wait_for_req_done(host, mrq);
> }
> EXPORT_SYMBOL(mmc_wait_for_req);
> --
> 2.17.1
>
prev parent reply other threads:[~2020-06-16 11:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 17:29 [PATCH] mmc: core: Add error check to avoid kernel panic caused by NULL pointer Corey Gao
2020-06-16 11:26 ` Ulf Hansson [this message]
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